WoW does lag some.
I really like the graphics. While they are a bit "cartoonish" and very colorful, I think that combo beats the hell out of some of the washed out and dark looking MMOGs. (Who wants a great video card that can display 16 million shades of brown?)
Get 1 MB of RAM if possible - all your games will love you, even if WoW isn't "the one".
Doctor buffs. Hehe. *Shudder* You can pretty much solo in WoW, no matter what your class, without needing some buff from another class.
Bottom line: This is a game you should try. I think it is worth the $50 just to check out. (Make a Dwarf and crunch through the snow in newbie-land!) Blizzard has done a LOT of things right in this game, even if it isn't perfect. If you are a fan of game design, and want to talk intelligently about what is right and wrong in the MMORPG world you need to spend some time in WoW. Have fun!